Expandable technology growth is changing drilling practices: here's what is offered, what is being developed and where this technology is headed

World Oil, July, 2003 by Robert E. Snyder, Perry A. Fischer

Recent years have seen an explosion of technologies related to expandable metals, and that trend has not abated. Much has been written about the potential sea change that this technology could have on well construction. The so-called monobore well, for example, when perfected, has the potential to reduce well costs and extend a reasonably large, non-telescoping ID to unprecedented depths. It is possible, perhaps likely, that this technology will someday be used in a majority of wells; and in the case of some items such as expandable screens--someday soon.

Just keeping track of what is offered can be a chore. So, World Oil compiled the present offerings of companies supplying expandable technology. In addition, we asked about the near and distant future of this technology. The companies featured are: Weatherford, Enventure, Halliburton, Baker Oil Tools, Schlumberger and READ Well Services.

The first section is an overview describing what is available now and how it is used, including brief examples of installations. The next section answers the question, "What are you working on that is in testing and development?" The last section asks about the future vision of these technology providers.

I. STATUS OF EXPANDABLE TECHNOLOGY

WEATHERFORD

Since 1998, Weatherford has led the industry in commercializing/installing Expandable Sand Screen (ESS*) technology that is rapidly becoming standard practice for reducing costs and enhancing production. It is now working toward the end game of providing a range of solid tubular expansion technologies that make the single-diameter (Or monobore) well a reality, both for high-end, challenging applications and lower profile wells. The company's Expandable Tubular Technologies are classified into three categories: Expandable Slotted Tubulars (EST), Solid Tubular Expansion (STE), and Expansion Systems, as explained here.

Expandable slotted tubulars (EST). The following discussions describe three sub-categories of EST: Expandable Sand Screens (ESS), Alternative Borehole Liners (ABL); and Expandable Completion Liners (ECL).

Expandable Sand Screens (ESS). As a major contributor to ESS technology, Weatherford has completed more than 225 installations worldwide with its range of expandable products, including 22.5 mi of ESS screen (Fig. 1), and the world's longest expansion, more than 4,900 ft of a 7,000-ft ESS. This track record verifies the growing adoption of ESS as a reliable, high-productivity sand control method.

ESS is being used extensively in a wide range of applications, including open-hole (74%), cased-hole (26%), multizone reservoirs and the world's first deployment in a multilateral North Sea well. Proven benefits include productivity improvements of up to 70%, compared to alternative sand control methods, and cost reductions of more than 20%.

Weatherford has a long ESS track record. An ESS screen first installed over 3 1/2 years ago in a North Sea, subsea, high-rare gas producer is still stable, sand-free and producing consistently.

A notable milestone was achieved in late 2002, when successful installation of 5 1/2-in. ESS with enhanced connectors for ConocoPhillips in Bohai Bay, marked the 150th global application. This was a multiwell project in Peng Lai field. The first six wells included two with cased-hole perforations (no sand control completion) and four with perforated casing, then ESS completions. The openhole deviated completion proved successful, leading to three additional wells being completed in the same manner.

ESS (Fig. 2) is available in sizes ranging from 2% in. to 5 1/2 in. It is the only compliant expandable screen that offers: borehole support; a large ID; high collapse resistance; and a large open area that resists plugging. With ESS screens, there is no need to use additional mud and fluids that can damage the screen; there is no rearrangement of produced sand into a low-permeability pack; and there are no hotspots.

Alternative Borehole Liners (ABL). The ABL has also proved successful, with a strong and growing track record. Operators in many producing areas must set casing strings ear-her or higher than desired due to problematic geological zones. Unstable formations can also prevent casing runs from reaching the target depth, resulting in need to run contingency casing strings. In both scenarios, as a result of being forced to run an additional string, wellbore diameter through the reservoir could be compromised, resulting in a well unable to meet production expectations, or even reach planned depths.

The ABL, a cemented, expandable slotted liner, can be used as a metal-to-rock solution to overcome these potential problems. For example, if a 9 5/8-in. casing string with a 8.681-in. ID is set higher than planned, an ABL can be installed below the string. This isolates the problem zone, but retains throughbore of 8.681 in. or larger. As a result, operators are able to retain hole size through the next section of the well, which could make the difference between the well being commercially viable or not.